 1 Water - Safe to Drink? Nepal
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|  4 Water source, Meatu District, Tanzania
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 5 Mwamongu Village water source, Tanzania
|  6 Water source in Dar es Salaam, Tanzania
|  7 The presence of the bacterium Escherichia coli indicates recent fecal contamination of water.
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 9 Components of the Portable Microbiology Laboratory
|  10 Portable Microbiology Laboratory. Materials for 25 water tests in gallon-sized plastic bag
|  11 Bob Metcalf holds the two Portable Microbiology Laboratory tests: Colilert MPN tube, and E. coli count Petrifilm.
|  12 Colilert: A presence/absence test for E. coli in 10 ml of water.
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 13 ONPG and MUG are the two substates for E. coli in Colilert
|  14 How to use Colilert MPN. Collect water in sterile WhirlPak (open well in Temeke Municipality, Dar es Salaam, Tanzania)
|  15 Carefully remove cap from Colilert tube
|  16 Use sterile pipette to add 10 ml of water source
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 17 Carefully replace cap
|  18 Shake tube to dissolve chemicals
|  19 Incubate at body temperature to allow 20-24 doublings of bacteria, usually 10-18 hours
|  20 Results appear in 12-24 hours. Clear = no coliform bacteria. Yellow (ONPG+) = coliform bacteria present
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 21 Use a battery-operated long UV light to shine on tubes. Blue fluorescence = MUG +, E. coli is present, water not safe to drink.
|  22 The best test for E. coli in foods: E. coli Count Petrifilm
|  23 Two substrates in Petrifilm for E. coli, lactose and BCIG
|  24 To use Petrifilm, label sample source and time
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